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Finding the Fourth Proportional to 449.60, 669.76 and 428.72

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Solution

The fourth proportional to 449.60, 669.76 and 428.72 is: 638.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    449.60 : 669.76 = 428.72 : x
  2. Step 2: Convert to fraction form
    449.60/669.76 = 428.72/x
  3. Step 3: Cross multiply
    449.60x = 669.76 × 428.72
  4. Step 4: Simplify right side
    449.60x = 287,139.51
  5. Step 5: Solve for x
    x = 287,139.51/449.60
  6. Step 6: Final answer
    x = 638.66

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.